Question

Va rog ajutati-ma la exercitiul 1.

Answer 1

/=fractie,supra
Ne ajutam de formulele:
(a+b)²=a²+2ab+b²
(a-b)²=a²-2ab+b²

a)=
x²-2x-x²=4
-2x=4
x=4:(-2)
x=-2

b)=
1-2y+y²=y²+2
-2y+y²-y²=2-1
-2y=1
y=-1/2

c)=
2z²+5=2z²+z
2z²-2z²+5=z
z=5

d)=
x²+x=x²+2x-x
x²+x=x²+x
x²+x-x²-x=0
0=0 
aici cred ca este o greseala la exercitiu

e)=
x²-2x+x-2-x²+x=0
0=0  
aici cred ca este o greseala la exercitiu 

f)=
2y²+2y-y-1=2y²-2y
2y²+y-2y²+2y=1
3y=1
y=1/3

g)=
0,25x²+x=0,25x²-x+1
0,25x²+x-0,25x²+x=1
2x=1
x=1/2

h)=
y²+2y-y²+y=3
3y=3
y=3/3
y=1

i)=
4z²-4z+1=4z²+z
4z²-4z²+1=z+4z
1=5z
5z=1
z=1/5

j)=
2+2√2x+x²=x²+1
2√2x+x²-x²=1-2
2√2x=-1
x=-1/2√2

k)=
x²+4x+4=x²+1
x²+4x-x²=1-4
4x=-3
x=-3/4

l)=
x²=x²-6x+9
x²-x²+6x=9
6x=9
x=9/6
x=3/2

Succes !